I'm going to ship a msi-package soon. It needs to be updated someday, so I wanted to set the property REINSTALL=ALL and REINSTALLMODE=voums by default. Therefore I added them in the properties manager but I still get the message, that the product is already installed.
You don't want to set the properties in the initial install because that will cause it to fail as an initial install. I think a better way to go is to make sure that your project is authored so that it can be upgraded, and set the proper properties when you author the update package.
There is a help topic on authoring a package so that it is upgradable but I don't remember offhand what it's titled, exactly.
